Filtering element

ABSTRACT

The invention relates to a filter or filtering element used alone or in juxtaposition with other elements of the same kind, for the purpose of purifying a fluid, which element constitutes an enclosure acting as a container for the pulverulent product and comprises a substantially rigid surrounding member optionally rigidly connected to a cover and base through which the fluid to be treated may pass, and is characterised in that at least one of the walls of said enclosure is made of a vinyl material which contracts under heat so as to enable the volume of the enclosure to be reduced after it has been completely filled with pulverulent product.

United States Patent 11 1 Giffard I ,Ban. 15, 1974 FILTERING ELEMENTPrimary Examiner-Samih N. Zaharna I Assistant Examiner-lvars Cintins[76] Inventor g g zz g s Houvenagle Att0rneyCushman, Darby & Cushman[22] Filed: Jan. 12, 1972 [57] ABSTRACT [2]] Appl. No.: 217,368

i The invention relates to a filter or filtering element ForelgnAppllcauon Pmmty Data used alone or in juxtaposition with other elementsof Oct. 26, 1971 France 7,138,401 the same kind, for the purpose ofpurifying a fluid, which element constitutes an enclosure acting as a[52] U S C! 210/282 206/46 229/DIG l2 container for the pulverulentproduct and comprises a [51] Bold 27708 substantially rigid surroundingmember optionally rig- [58] Field R 46 FC' idly Conngcted to a Cover andbase through which the 210/282, 283, 350, 484; 229/DIG. l2; 99/77.1

fluid to be treated may pass, and is characterised in that at least oneof the walls of said enclosure is made of a vinyl material whichcontracts under heat so as to enable the volume of the enclosure to bereduced after it has been completely filled with pulverulent product.

11 Claims, 3 Drawing Figures FILTERING ELEMENT FIELD OF THE INVENTIONThe invention relates to a filter or filtering element containing apulverulent product and used in the purification of fluids.

BACKGROUND OF THE INVENTION It is well known that the main drawback offilters of this kind results from the caking of the powder, for exampleactive charcoal, in their containers under the effect either of thevibrations of the installation or of the thrust of the fluid. It is wellknown that this caking not only alters the pressure-loss suffered by thefluid, but also causes segregation of particles of different sizes sothat the filtration conditions are altered during the period of use ofthe filter. This is particularly so when the filtering elements have alarge active surface. Filters of this latter type also carry thedrawback of being heavy as result of the metal frame for impartingrigidity to them, the powder being contained between two layers offelted fibres known as non-woven fibres. In practice, therefore, suchfilters can only be used in the horizontal position since in any otherposition the upper portion of the active surface would cease to exercisea suitable filtering effect as it would no longer be in contact with thepowder that will have moved downwards by gravity.

OBJECT OF THE INVENTION The invention aims at providing a filterstructure that eliminates these drawbacks.

SUMMARY OF THE INVENTION The filtering element in accordance with theinvention constitutes an enclosure acting as a container for thepulverulent products and comprises a substantially rigid surroundingmember optionally rigidly connected to a cover and a base through whichthe fluid to be treated may pass, and is characterised in that at leastoneof the walls of said enclosure is made of a vinyl material whichcontracts under heat, so as to enable the volume of the enclosure to bereduced after it has been completely filled with pulverulent product.

Thus, because'of the diminution of volume resulting from thecontraction, the pulverulent product undergoes compression which expelsthe air between the particles and compacts the filtering mass, thuspreventing subsequent caking as well as segregation.

To facilitate reduction of the volume of the enclo sure, said wall madeof material which contracts under heat is the base of the enclosure, andthis base takes the form of a dish or cup, the upper edges of which areattached to the lower edges of the surrounding member.

The filtering element may be used separately when a relatively smallfiltering surface is required. On the other hand, in the case of largefiltering surfaces, the filtering element is welded by the edges of itscollar to other elements, preferably of the same kind, so as toconstitute the active surface of a filter.

Other features and advantages of the invention will emerge from thefollowing description which refers to the accompanying drawings,provided by way of nonlimiting example, and which will explain how thepresent invention may be put into use.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 illustrate twoembodiments of the invention.

FIG. 3 is a diagrammatic view showing nine filtering elements groupedtogether to form the active surface of a filter.

DESCRIPTION OF SPECIFIC EMBODIMENTS As will be seen from these Figures,the filtering element according to the invention comprises a cover F anda base F which are solidly interconnected by a surrounding member C, theenclosure thus formed being completely filled with the pulverulentfiltering product In the case of the embodiment illustrated in FIG. I,the base F is moulded to the form of a dish from a sheet of feltednon-woven fibres, the upper edges of which are secured (for example byH. F. welding) to the lower edges of the surrounding member C, and insuch a manner as to permit sufficient contraction of the PVC. fibres(for example fibres sold in France under the trade-name Rhovyl) in orderto effect a considerable diminution of the enclosure and consequentlyefficient compression of the powder, thereby expelling the air betweenthe particles.

In the case of the embodiment illustrated in FIG. 2, the dishconstituting the base F has walls which extend upwards to the cover Fthe surrounding member C merely acting as a simple reinforcing coveringinside or outside the dish.

In these two cases, the surrounding member is made of a semi-rigidplastics material and is attached to the cover and base either bybonding or welding, and in particular by high-frequency welding.

Particularly, in the case of low capacity filters it would also bepossible to rigidize the walls of the dish of the second embodiment byhardening said walls either by the use of a thermosetting bonding agent,or by vitrifying them by a heating process, for example a high-frequencymethod, and this would render the surrounding member C unnecessary.

In most cases the element is provided with a collar or flange B forfixing it in the structure of the filter. This collar, which may also beused as a support for the cover F may be integral either with thesurrounding member C or with the dish constituting the base F or withboth.

The element may be used separately if its surface is not large, butpreferably it is arranged in juxtaposition (FIG. 3) with other similarelements to form the general filtering surface.

The Applicant has in fact found that if the surface of the dish or cupis too great, the quantity of powder is too large for the mixture toremain in the filled-up state without segregation, which segregation issubsequently promoted by a lower degree of compression due on the onehand to the deformation of the base by the charge and on the other handto the spreading of the effect of contraction over a greater volume.

In the case of FIG. 3, the dishes are connected by their collars orflanges B, or are assembled in a common supporting plate.

What is claimed is:

1. A filtering element housing a pulverulent product for use in fluidpurification comprising: a first porous means through which fluid to betreated may pass; a

second porous means through which the fluid to be treated may pass andbeing operatively connected to the first means; the first and secondmeans define a pulverulent enclosure therebetween, wherein the enclosureis completely filled by the pulverulent; at least one of the first andsecond means being made of a heat contractable material, which is heatedto contract causing the volume of the enclosure to also contract so asto compress the pulverulent thereby, expelling air from the pulverulent,whereby caking and segregation of the pulverulent during use areeliminated.

2. The filtering element according to claim 1 further comprising: asubstantially rigid surrounding member interconnected between the firstmeans, and the second means for reinforcing the rigidity of thefiltering unit.

3. The filtering element according to claim 1 wherein at least one ofthe first and second means is made of a substantially rigid material.

4. The filtering element according to claim 1 wherein the heatcontractable material is comprised of a vinyl material.

5. The filtering element according to claim 2 wherein the first meansmade of material which contracts under heat is a base and takes a formof a cup, the upper edges of which are connected to the lower edges ofthe surrounding member.

6. The filtering element according to claim 2 wherein the surroundingmember is made of rigidized felted non-woven fibres.

7. The filtering element according to claim 1 wherein the second meansis made ofa substantially rigid plastic material.

8. The filtering element according to claim 7 wherein the filteringelement is rigidized by having the first and second means and thesurrounding member interconnected with respect to each other by a H. F.weld.

9. The filtering element according to claim 2 characterized in that thesurrounding member comprises a horizontal collar.

10. The filtering element according to claim 9 wherein the collar isconnected at the edge thereof to at least other filtering means to forman active filter surface that presents plurality of filters which spreadthe effect of contraction of the pulverulent over a greater volume,thereby eliminating segregation of the pulverulent.

11. The filtering element according to claim 10 wherein the otherfiltering means are comprised of a plurality of filtering elements.

1. A filtering element housing a pulverulent product for use in fluidpurification comprising: a first porous means through which fluid to betreated may pass; a second porous means through which the fluid to betreated may pass and being operatively connected to the first means; thefirst and second means define a pulverulent enclosure therebetween,wherein the enclosure is completely filled by the pulverulent; at leastone of the first and second means being made of a heat contractablematerial, which is heated to contract causing the volume of theenclosure to also contract so as to compress the pulverulent thereby,expelling air from the pulverulent, whereby caking and segregation ofthe pulverulent during use are elIminated.
 2. The filtering elementaccording to claim 1 further comprising: a substantially rigidsurrounding member interconnected between the first means, and thesecond means for reinforcing the rigidity of the filtering unit.
 3. Thefiltering element according to claim 1 wherein at least one of the firstand second means is made of a substantially rigid material.
 4. Thefiltering element according to claim 1 wherein the heat contractablematerial is comprised of a vinyl material.
 5. The filtering elementaccording to claim 2 wherein the first means made of material whichcontracts under heat is a base and takes a form of a cup, the upperedges of which are connected to the lower edges of the surroundingmember.
 6. The filtering element according to claim 2 wherein thesurrounding member is made of rigidized felted non-woven fibres.
 7. Thefiltering element according to claim 1 wherein the second means is madeof a substantially rigid plastic material.
 8. The filtering elementaccording to claim 7 wherein the filtering element is rigidized byhaving the first and second means and the surrounding memberinterconnected with respect to each other by a H. F. weld.
 9. Thefiltering element according to claim 2 characterized in that thesurrounding member comprises a horizontal collar.
 10. The filteringelement according to claim 9 wherein the collar is connected at the edgethereof to at least other filtering means to form an active filtersurface that presents plurality of filters which spread the effect ofcontraction of the pulverulent over a greater volume, therebyeliminating segregation of the pulverulent.
 11. The filtering elementaccording to claim 10 wherein the other filtering means are comprised ofa plurality of filtering elements.